fio is an I/O tool meant to be used both for benchmark and stress/hardware verification. It has support for 19 different types of I/O engines (sync, mmap, libaio, posixaio, SG v3, splice, null, network, syslet, guasi, solarisaio, and more), I/O priorities (for newer Linux kernels), rate I/O, forked or threaded jobs, and much more. It can work on block devices as well as files. fio accepts job descriptions in a simple-to-understand text format. Several example job files are included. fio displays all sorts of I/O performance information, including complete IO latencies and percentiles. Fio is in wide use in many places, for both benchmarking, QA, and verification purposes. It supports Linux, FreeBSD, NetBSD, OpenBSD, OS X, OpenSolaris, AIX, HP-UX, Android, and Windows.

Siege is a regression test and benchmark utility. It can stress test a single URL with a user defined number of simulated users, or it can read many URLs into memory and stress them simultaneously. The program reports the total number of hits recorded, bytes transferred, response time, concurrency, and return status. Siege supports HTTP/1.0 and 1.1 protocols, GET and POST directives, cookies, transaction logging, and basic authentication. Its features are configurable on a per user basis.

Tcpreplay is a set of Unix tools which allows the editing and replaying of captured network traffic in pcap (tcpdump) format. It can be used to test a variety of passive and inline network devices, including IPS's, UTM's, routers, firewalls, and NIDS.

pv (Pipe Viewer) is a terminal-based tool for monitoring the progress of data through a pipeline. It can be inserted into any normal pipeline between two processes to give a visual indication of how quickly data is passing through, how long it has taken, how near to completion it is, and an estimate of how long it will be until completion.

BRL-CAD is a powerful constructive solid geometry solid modeling system that includes an interactive geometry editor, ray-tracing support for rendering and geometric analysis, path-tracing for realistic image synthesis, network distributed framebuffer support, and image and signal-processing tools.

Tsung is a distributed load testing tool. It is protocol-independent and can currently be used to stress HTTP, WebDAV, PostgreSQL, MySQL, LDAP, AMQP, and XMPP/Jabber servers. It simulates user behavior using an XML description file, reports many measurements in real time (statistics can be customized with transactions, and graphics generated using gnuplot). For HTTP, it supports 1.0 and 1.1, has a proxy mode to record sessions, supports GET, POST, PUT, and DELETE methods, cookies, and basic/digest authentication. It also has support for SSL, WebSocket, and BOSH.

Performance Co-Pilot (PCP) is a framework and set of services for supporting system-level performance monitoring and performance management. It provides a unifying abstraction for all of the interesting performance data in a system, and allows client applications to easily retrieve and process any subset of that data using a single API. A client-server architecture allows multiple clients to monitor the same host, and a single client to monitor multiple hosts. Archive logging and replay are integrated so that a client application can use the same API to process real-time data from a host or historical data from an archive.

Bandwidth is primarily a memory bandwidth benchmark, but it can also measure network bandwidth. It measures the maximum memory bandwidth of each part of the memory system, including main memory, L1, L2, and L3 caches, framebuffer memory, and register-to-register. For many tests, it performs both sequential memory accesses as well as random memory accesses to provide a more real-world performance estimate. The tests support Linux (Intel), Windows/Cygwin, and Mac OS X. Its core routines are in assembly for x86 and x86-64 architectures with both SSE4 and AVX support. Bandwidth also includes automatic graphing of the results, stored to a BMP image file. The network bandwidth tests support Linux, Mac OS X, and Windows/Cygwin.

Calamaris parses the logfiles of a wide variety of Web proxy servers and generates reports about peak-usage, request-methods, status-report of incoming and outgoing requests, second and top-level destinations, content-types, and performance.